Man's Best Friends Know Who Their Best Friends Are

Dogs can help themselves by deciphering humans' social interactions.

Researchers and pet owners have long known that dogs can learn spoken commands and understand certain human gestures. But can they actually eavesdrop—that is, pick up information simply by watching interactions between people? Animal cognition researcher Sarah Marshall-Pescini and her colleagues at the University of Milan believe that dogs do indeed engage in interspecies snooping.

To test their hypothesis, the scientists allowed 84 dogs to observe, one by one, food-sharing interactions between humans. During each trial, a human “beggar” repeatedly approached two other people holding bowls of aromatic sausages. (Mmm. For more on this topic, see 20 Things.) When the beggar asked for a bite, one of the sausage keepers rejected her, saying no and flicking one hand in a dismissive shooing gesture. The other person willingly shared, saying “have it” while offering a morsel. After the beggar left the room, the dog was let off its leash.

Once freed, pooches could approach either one of the people, each still holding bowls of sausage. The dogs decided to beg from the charitable person five times as often as from the stingy one. “It was intriguing to discover that dogs assess us in terms of how generous we are,” Marshall-Pescini says, perhaps because “they view us as potential cooperative partners.” That, or an easy mark for delicious meats.